Plural endless grates, including clutch operating means



E. C. MILLER PLURAL ENDLESS GRATES, INCLUDING CLUTCH OPERATING MEANS Jan. 16, 1951 2 Sheets-Sheet 1 Filed June 25, 1948 /M/f/v raf? hm E 6. Mu .L En.

47' Tak/ver Jan. 16, 1951 E. c. MILLER PLURAL ENDLEss GRATIS, INCLUDING CLUTCH OPERATING MEANS 2 Sheets-Sheet 2 Filed June 25, 1948 N .ME N

/N VEA/roe EARL? C. MVL/.ER

n N R m T H Patented Jan. 16, 1951 UNITED sTATEs'rArENT OFFICE PLURAL ENDLESS GRATES, INCLUDING CLUTCH OPERATING MEANS Earle C. Miller, Worcester, Mass., assignor to Riley Stoker Corporation, Worcester, Mass., a corpo-.-

ration of Massachusetts Application June 23, 1948, Serial No. 34,602

Claims. (Cl. 110-40) when the demand for heat is comparatively low.

As heretofore constructed such furnaces have required a separate driving means for each grate, each such driving means including a motor or engine and suitable speed reducing mechanism of a costly nature. As a consequence prior furnaces of this general type have been unduly complicated and expensive.

It is accordingly one object of the invention to provide a comparatively simple, inexpensive and dependable furnace having two endless grates one of which may be taken out of service when not needed to maintain the current heat requirements.

It is a further object of the invention to provide a furnace having two laterally adjacent endless grates, together with a single and rugged mechanism whereby one or both of the grates may be connected to a single driving means.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

Referring to the drawings illustrating one embodiment of the invention, and in which like reference numerals indicate like parts,

Fig. 1 is a fragmentary horizontal section through an endless grate furnace, the section being taken substantially on the line I--I of Fig. 2;

Fig. 2 is a fragmentary vertical section taken on the line 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1, showing a slight modification; and

Fig. 4 is a view similar to Fig. l, showing a further modification.

The furnace illustrated in Figs. 1 and 2 comprises a combustion chamber having two upright side walls Ill and a front wall II. Two endless grates I2 and I4 of any suitable construction are mounted side by side within the combustion chamber. An opening I5 is provided in the front wall II above each grate, and in front of each opening there is mounted a fuel feeding mechanism I5 of the well-known spreader or sprinkler type. This mechanism comprises a hopper IB for coal or other suitable fuel, a reciprocable plunger I9 beneath the hopper, and a bladed rotor 20 in position to receive coal as it is delivered thereto from the hopper by means of the plunger. Each rotor 20 serves to throw the fuel rearwardly through the corresponding opening I5 to maintain a bed of burning fuel on the associated grate. In the particular furnace shown, the fuel supporting portion of each grate travels slowly in a forward direction toward an ash pit 22 at the front of the furnace.

The front portion of the grate I2 is driven by a pair of sprocket wheels 24 which are mounted upon a horizontal hollow rotatable shaft 25 supported in a pair of bearings 23. Similarly the front portion of the grate I4 is driven by a pair of sprocket wheels 28 which are mounted upon a horizontal hollow rotatable shaft 29 in axial alignment with the shaft 24 and supported in a pair of bearings 3l). The bearings 26 and 30 are carried by a horizontal beam 3|. A rotatable drive shaft 33 extends through both the hollow shafts 25 and 29, this drive shaft being supported in a pair of bearings 34 carried by the beam 3l. Oneof the bearings 34 is located between the adjacent ends of the hollow shafts, and the other bearing is located near one end of the drive shaft. On the other end of the drive shaft there is mounted a half-coupling 35 so that the shaft may be connected to a suitable source of power.

Suitable clutch mechanism, preferably of the jaw clutch type, are provided to connect the drive shaft 33 independently and releasably to the hollow shafts 25 and 29. For this purpose a jaw clutch member 31 is mounted on the outer end of each hollow shaft, and a cooperating jaw clutch member 38 is slidably keyed to the drive shaft adjacent to each member 31. An operating lever 39 is provided for each of the sliding members 38, these levers being fulcrumed on the beam 3l.

The operation of this embodiment of the invention will now be apparent from the above disclosure. By manipulating the levers 39 the hollow shafts 25 and 29 can be independently clutched to the drive shaft. Consequently either of the grates I2 and I4 can be shut down as desired while the other grate remains in operation. Thus it is feasible to operate the furnace at comparatively low rates if desired. When operating in this manner, the inactive grate should be protected from radiant heat by covering it with a layer of ashes or other suitable material.

Referring now to the modification shown in Fig. 3, this construction differs from that of Fig. 1 in that the bearings 34 of the latter have been omitted, and the drive shaft 33 is rotatably supported in bearing sleeves 4I mounted within the hollow shafts 25 and 29. The operation will be similar to that of the Fig. l embodiment.

In Fig. 4 thefconstruction differs from Fig. 1

3 in that the hollow shaft 29, its bearings 30, and the corresponding clutch have been omitted, and the sprocket wheels 28 are mounted upon the drive shaft 33. The bearings 34 for this shaft are mounted on the beam 3| in positions adjacent to the respective sprocket wheels 28. With this construction both grates may be operated together, or the grate I2 may be stopped by disconnecting the clutch, while the grate I4 remains in service, thus permitting satisfactory operation of the furnace under low load conditions. While this embodiment does not permit the operation of grate I2 while grate I4 is shut down, it nevertheless provides a less expensive mechanism with somewhat fewer parts than in Fig. 1.

It will be recognized that the present invention provides a simple and dependable furnace construction including two endless grates arranged side by side and requiring only a single driving means, with a releasable clutch whereby one grate may be shut down while the other remains in operation. This construction has important advantages over the prior practice in this art.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A fuel burning apparatus comprising two endless grates located side by side, a rotatable drive shaft, means to connect the drive shaft to one of said grates, a hollow rotatable shaft coaxial with the drive shaft, the drive shaft extending through the hollow shaft, means,l to connect the hollow shaft to the other grate and a clutch mechanism releasably connecting the hollow shaft to the drive shaft.

2. A fuel burning apparatus comprising two endless grates located side by side, a rotatable drive shaft, means to connect the drive shaft to one of said grates, a hollow rotatable shaft coaxial with the drive shaft, the drive shaft extending through the hollow shaft, means to connect the hollow shaft to the other grate, and a clutch mechanism releasably connecting the outer end of the hollow shaft to the adjacent portion of the drive shaft.

3. A fuel burning apparatus comprising two endless grates located side by side, a separate hollow rotatable shaft connected to each grate to drive the same, the hollow shafts being axially aligned, a rotatable drive shaft extending through both the hollow shafts, and separate clutch mechanisms releasably connecting the respective hollow shafts to the drive shaft.

4. A fuel burning apparatus comprising two endless grates located side by side, a separate hollow rotatable shaft connected to each grate to drive the same, the hollow shafts being axially aligned, a rotatable drive shaft extending through both the hollow shafts, and separate clutch mechanisms releasably connecting the outer end portions of the respective hollow shafts to the adjacent portions of the drive shaft.

5. A fuel burning apparatus comprising two endless grates located side by side, a pair of driving sprocket wheels for each grate, a hollow rotatable shaft supporting the sprocket wheels for one of the grates, a rotatable drive shaft supporting the sprocket wheels for the other grate and extending through the hollow shaft, and a clutch mechanism releasably connecting the hollow shaft to the drive shaft.

EARLE C. MILLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 334,047 Poore Jan. 12, 1386 662,769 Crowe Nov. 27, 1900 824,534 Einfeldt June 26, 1906 

